Is there a connection between love and delusion?

People with positive illusions about their relationship are more satisfied, score higher on love and trust and have fewer problems:

It is proposed that satisfying, stable relationships reflect intimates’ ability to see imperfect relationships in somewhat idealized ways-to make a leap of faith. Both members of dating and married couples completed a measure of relationship illusions, tapping idealized perceptions of the partners’ attributes, exaggerated perceptions of control, and unrealistic optimism. Results of concurrent analyses revealed that relationship illusions predicted greater satisfaction, love, and trust, and less conflict and ambivalence in both dating and marital relationships. A longitudinal follow-up of the dating sample revealed that relationships were more likely to persist the stronger individuals’ initial illusions. Relationship illusions also predicted increases in later satisfaction but not vice versa. These results suggest that positive illusions capture a prospective sense of conviction or security that is not simply isomorphic with satisfaction.

Source: “A Leap of Faith? Positive Illusions in Romantic Relationships” from Personality and Social Psychology Bulletin

This lines up with research I’ve posted before. Positive illusions about your partner’s attractiveness correlate with relationship quality:

The present research examined the existence of positive illusions about a partner’s physical attractiveness and its relations to relationship quality. Positive illusions were assumed to exist when individuals rated their partner as more attractive than their partner rated him or herself. In two Dutch community samples of 117 and 203 married or cohabiting heterosexual couples, both partners rated their own and their partner’s facial and bodily attractiveness. In Study 2, both partners completed three measures of relationship quality. Both studies found evidence for the existence of positive illusions about a partner’s physical attractiveness. Moreover, Study 2 found clear positive illusion actor effects for relationship quality. This association differed by age of couples.

Source: “Positive illusions about a partner’s physical attractiveness and relationship quality” from the journal “Personal Relationships”